Armpits for fashion reasons? Quite 'recently'.

Prior to 1915, body hair on a woman was seen as a non-issue thanks to the straight-laced styles of the Victorian era — with women draped and buttoned up to the chin, shaving your armpits was as odd and unnecessary as shaving off your eyebrows. But when Gillette realized he could double his profits by doubling his customers and introducing women as shoppers, he got to working on how to bring blades into powder rooms.

I got it from here.

Other, older, examples of other shaving practices? Read this!